Magneto impulse starter.



J. R. STARK. MAGNETO IMPULSE STARTER.

APPLICATION FILED mi. 24. 1912.

Patented July 31; 1917.

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UNITED STATES PATENT OFFICE.

JOHN ROY STARK, OF RACINE, WISCONSIN.

MAGNE'IO IMPULSE STARTER.

Application filed February 24, 1917.

To all whom it may concern:

Be it known that I, JOHN Ror STARK, a citizen of the United States,residing at 1516 Thurston Ave, Racine, Wisconsin, have invented certainnew and useful Improvements in Magneto Impulse Starters, of which thefollowing is a full and complete specification, reference being hadtherein to the accompanying drawings.

This invention relates to mechanism for driving a magneto ignitiongenerator from an internal combustion motor, this mechanism being of atype which employs a resilient connection between the driving means andthe magneto rotor shaft, which at low engine speeds is alternatelyplaced under tension and then released, accelerating the speed of themagneto rotor relative to that of the driving means at each ignitionperiod, and thereby producing a strong and eflicient spark at low enginespeeds.

In devices of this nature heretofore used, it has been found that theresilient connection between the driving means and the magneto rotorbecomes troublesome at high speeds, the same introducing a variable laginto the drive on account of the variable magnetic torque of the magnetorotor, this lag being greatest just at a time when the spark shouldoccur in an early or advanced position, (at high engine speeds), andhence the ellioiency of the magneto is more or less affected by suchaction. This difficulty may be overcome by the use of a very stiff resilient means or spring, but at low speeds, the use of such a springthrows considerable strain on the release mechanism and as aconsequence, the same is soon worn out or broken.

It is the general object of this invention to provide a simple structureof the class described to produce an efficient spark at low enginespeeds, and which does not interfere with the proper operation of themagneto at normal or high engine speeds.

It is a further object of this invention to provide a structure which isentirely automatic in action, and in which the non-synchronous operationof the magneto at starting, automatically becomes synchronous as soon asthe engine attains its normal speed.

It is a still further object of the presentinvention to provide a simplecombined supporting and inclosing means for such structure.

For the purpose of rendering the in- Specification of Letters Patent.

Patented July 31, 191 '7.

Serial No. 150,749.

vention more clear, reference is bad to the accompanying drawings inwhich Figure 1, shows a cross section elevational view of one form ofthe device, in structural relation with a magneto; Fig. 2, shows asection along line 22 of Fig. 1; Fig. 3, is a plan view; and Fig. 4,shows in detail, the structure of the dog and release arms and theirrelation to the driving and driven members.

The rotor shaft 1 of a magneto 2 has fastened or keyed upon its end adisk 8, shaft 1 rotating in a ball bearing 6 located in an end plate 5,which as shown is structurally integral with the magneto 2, the bearing6 forming the front magneto bearing. It should be understood, however,that if desired the invention may be embodied in an individual structureadapted to be utilized in combination with any of the well known typesof magnetos. Supported by the casing a, is a second bearing 7, in whicha shaft 3 is mounted in axial alinement with shaft 1. Secured upon shaft3 is a second disk 9, provided with a central hub 10, having a circularrecess into which fits a boss or projection 11 fixed upon disk 8, thisprojection serving to center and support themembers 8 and 9 in properrelation to each other. Carried upon the inner face of the disk 9, andprojecting perpendicularly therefrom, are two pivot pins 12 and 12,these pins being located at diametrically opposite points on the saiddisk. Located on the inner face of the disk 8, and similarly mounted,are two other pivot pins 13 and 13. Mounted upon and connecting thepivot pins 12 and 13, is a flat steel spring 14, a second spring 15being similarly mounted upon the pins 12 and 13 The pivot pins are solocated in the disks 8 and 9 and the disks so angularly positioned toeach other, that the springs 14 and 15 lie parallel to each other andare both tangent to a circle whose center is located at the axis ofrotation of the disks.

Located at diametrically opposite points on the edge of disk 8 are twonotches 16, these notches being located in the center of depressionsformed in the edge of the disk. This is clearly shown in Fig. 4, inwhich the dotted lines show the original contour of the disk. The edgeof disk 9 carries two depression cam surfaces 17 located diametricallyopposite each other, as shown in Fig. 2.

The release mechanism which is mounted in a recess 18, formed in thecasing above the disks 8 and 9, consists of a hub 19 with integral arms21 and 22, arm 21 being pro vided at its end with a dog or projection24, and the arm 22, with a fiber block 23, this block being located tocooperate with the depression cams 17 of the disk 9, while the dog 24cooperates with the notches 16 of disk 8. The hub 19 is fulcrumed by thetwo projecting shafts 20 which find bearing in the two portions of thecasing 4 and 5. As shown in Fig. 1, the casing members 4 and 5completely inclose the structure and a filling plug 25 may be used tointroduce a suitable lubricant into the interior of the casing. Thepiece 18 is a portion of the housing 4 which extends across the recess18 and is of assistance centering the housing 4 on the bearing plate 5.

The operation of the device is as follows :Assuming the shaft 3, whichis positively geared to the engine crank shaft, to be rotated in ananti-clock-wise direction, the disk 9 will rotate the disk 8 by means ofthe connection existing between the two disks in the form of the springs14 and 15. The disk 8 will continue to rotate until the dog 24 drops bygravity into the notch 16, this action being rendered possible, owing tothe fact that the fiber block 23 has already entered one of thedepression cam surfaces 17 of the disk 9, thereby allowing the dog 24 todrop far enough to cooperate with the notch. As the driving member ordisk 9 continues to rotate, and the driven member or disk 8 is heldstationary by the dog 24, the springs 14 and 15 are deformed into thecurved positions shown in dotted lines in Fig. 2, thereby storingpotential energy. As the disk 9 rotates still further, the cam surface17 passing under the fiber block 23, gradually returns to normal,lifting fiber block 23, and through arms 21 and 22, lifting'the dog 24out of the notch 16, thereby releasing the disk 8 and allowing the sameto suddenly rotate under the action of the en ergy obtained from thesprings 14 and 15 as they assume their normal parallel positions. Themagneto rotor is thereby given two quick impulses per revolution of theshaft 3, the notches 16, 16, and the cam surfaces 17, 17 being angularlylocated with reference to the magneto rotor, to give the impulses at theproper spark producing positions of the rotor.

After the engine has started and its speed becomes normal, theperipheral speed of the disks 8 and 9 becomes too great to allow the dog24 time to drop far enough into the depressions in the edge of disk 8 toenter the notches 16 and the dog and release mechanism therebyautomatically become inoperable. The magneto rotor is now driven atsynchronous speed, the necessary torque being transmitted from thedriving member 9 to the driven melnber 8 by means of the flat springs 14and 15. As these springs are tangent to a circle with the axis ofrotation as its center, the greater part of the power is transmittedthrough the springs in the form of a thrust along their axes, and thesprings therefor offer considerable resistance to any initialdeformation. After initial deformation has occurred, however, theremaining deformation of the springs 14 and 15 requires much lesseffort, and the flat springs therefor form resilient connecting meanspossessing a variable deformation resistance. It is therefore possiblein a struc ture of the type just set forth, to design the flat springsso that they will transmit the necessary torque to drive the magnetorotor without deformation, and yet when the springs function atstarting, they will not throw a heavy and excessive strain on therelease mechanism.

As shown in the drawings, the springs 14 and 15 should be provided withsome means for preventing an inward or reverse deformation, this beingprevented in the structure shown by placing the springs tangent to thehub 10.

What I claim is 1. In a magneto impulse starter, the combination with adriving member, of a driven member, and means comprising a flat springfor connecting said driving member and said driven member together, saidspring being pivotally connected to both of said members.

2. In a magneto impulse starter, the combination of a driving shaft anda driving disk mounted thereon, with a driven shaft and a driven diskmounted thereon, said driven shaft being in alinement with said drivingshaft; and means for connecting said driving disk and driven disktogether comprising a plurality of fiat springs, the axes of which aretangential to a circle whose cen- 'ter is in the axis of rotation of thedriving shaft.

3. In a magneto impulse starter, the combination with a magneto rotorshaft, of a driven disk fixed thereto, a driving disk coaxially relatedto said driven disk, flat resilient means connecting said driving anddriven disks together, a notch in the edge of said driven disk, a dogarranged to cooperate with said notch to prevent rotation of said drivendisk, and means carried by said driving disk to disengage said dog fromsaid 1 notch.

4. In a magneto impulse starter, the combination with a magneto rotorshaft, of a driven disk fixed thereto, a driving disk 00- axiallyrelated to said driven disk, yielding means possessing variabledeformation resistance connecting said driving and driven diskstogether, a notch in the edge of said driven disk, a dog arranged tocooperate with said notch to prevent rotation of said driven disk, andmeans carried by said driving disk to disengage said dog from saidnotch.

5. In a magneto impulse starter, the combination with a magneto rotorshaft, of a driven disk fixed thereto, a driving disk coaxially relatedto said driven disk, resilient means connecting said driving and drivendisks together, a depression in the edge of said driven disk; a notchlocated in said depression, a dog arranged to enter said notch under thein uence of gravity to prevent rotation of said driven disk, and meanscarried by said driving disk to disengage said dog from said notch, saiddepression being of such contour as to prevent the dog from entering thenotch when the peripheral speed of the driven disk attains a certainvalue.

6. In a magneto impulse starter, the combination with a magneto rotorshaft, of a driven disk fixed thereto, a driving disk coaxially relatedto said driven disk, resilient means comprising a plurality of flatsprings for connecting said driving and driven disks together, adepression in the edge of said driven disk, a notch located in saiddepression, a dogarranged to enter said notch to prevent rotation ofsaid driven disk, and means carried by said driving disk to disengagesaid dog from said notch, said depression being of such contour as toprevent the dog from entering the notch when the peripheral speed of thedriven disk attains a certain value.

7. In a magneto impulse starter, the combination with a magneto rotorshaft, of a driven disk fixed thereto, a driving disk coaxially relatedto said driven disk, resilient means for connecting said driving anddriven disks together, a depression in the edge of said driven disk, anotch located in said depression, a dog arranged to enter said notch toprevent rotation of said driven disk, and means carried by said drivingdisk to disengage said dog from said notch, said depression being ofsuch contour as to pre-' vent the dog from entering the notch when theperipheral speed attains a certain value.

8. In a device of the class described, the combination of two casingmembers cooperating with each other to form a closed casing, a shaftrotatably supported by each of said casing members; magneto impulsestarter mechanism connected to said shafts, and located within saidcasing, and compris ing driving and driven members, resilient meansconnecting said members together, and stop and release mechanism forcontrolling the operation of said members, said stop and releasemechanism being located in a recess formed at the top of said casing.

9; In a device of the class described, the combination of two casingmembers cooperating to form a closed casing, a shaft rotatably supportedby each of said casing members, said shafts being in axial alinement;magneto impulse starter mechanism connected to said shafts and locatedwithin said casing, and comprising driving and driven members, resilientmeans for connecting said members together, and stop and releasemechanism for controlling the operation of said members, said stop andrelease mechanism being located in a recess formed at the top of saidcasing.

In testimony whereof I have hereunto set my hand.

JOHN ROY STARK.

Copies 01 this patent may be obtained (or five cents each, by addressingthe "Commissioner of Patents, Washington, D. G.

